libvirt_vm: Add exists() for libvirt VM class.

Signed-off-by: Yu Mingfei <yumingfei@cn.fujitsu.com>
virsh: Add migrate_setmaxdowntime method.

Signed-off-by: Yu Mingfei <yumingfei@cn.fujitsu.com>
libvirt.test: Add test module for virsh migrate-setmaxdowntime.

Signed-off-by: Yu Mingfei <yumingfei@cn.fujitsu.com>
Merge pull request #488 from yumingfei/virsh_migrate_setmaxdowntime

Libvirt:Virsh migrate setmaxdowntime
virttest-virsh: fix prompt in VirshSession to support prompt 'virsh >'

When connect --readonly in a virsh session, the prompt changes to 'virsh >'.

Signed-off-by: yangdongsheng <yangds.fnst@cn.fujitsu.com>
virt: add method 'get_uri_with_transport' into libvirt_vm.

Signed-off-by: yangdongsheng <yangds.fnst@cn.fujitsu.com>
virttest.virsh: Add connect function for virsh module.

Signed-off-by: yangdongsheng <yangds.fnst@cn.fujitsu.com>